1. Field of the Invention
This invention relates to a wireless communication network system such as a wireless LAN (local area network) system which has a host device (a central device) and a plurality of terminal devices which can communicate with the host device by wireless, for example, radio or light.
It should be understood herein that reference to "optical" and "light" include infrared radiations as well as visible light.
2. Description of the Prior Art
A general wireless LAN system of the CSMA (carrier sense multiple access) type has a central controller (a host device) and a plurality of terminal devices which can communicate with the central controller by wireless. Generally, each of the terminal devices is designed to provide the following function. In cases where the terminal device is required to transmit a signal toward the central controller, the terminal device detects whether or not a signal from the central controller is currently received. The terminal device executes signal transmission when a signal from the central controller is detected to be currently absent. Otherwise, the terminal device does not execute signal transmission.
In the wireless LAN system, when two different terminal devices simultaneously transmit signals toward the central controller, the transmitted signals tend to interfere with each other. The signal interference causes a failure in communication among the terminal devices and the central controller.